1. Field of the Invention
The present invention relates to a cooling device for cooling an interior of a sealed housing for accommodating a heat-generating member such as an electronic part.
2. Description of Related Art
Conventionally, a heat-generating member such as an electronic part is used while being located in a sealed housing. Because outside air cannot be circulated inside the housing for ventilation in this case, a heat exchange between air inside the housing and air outside the housing is performed to cool the heat-generating member.
For example, in a cooling device described in JP-B2-2-3320, a heat pipe is disposed along a side wall surface of a housing. Heat exchange between air inside the housing and air outside the housing is performed through the heat pipe. That is, as shown in FIG. 15, a lower portion 210 of the heat pipe 200 is disposed within the housing having a high temperature, and an upper portion 220 of the heat pipe 200 is disposed outside the housing. However, when the heat pipes are disposed in multiple layers, it is necessary to provide an air-blowing passage at the outside of the lower portion 210 or the upper portion 220 as shown by an arrow C in FIG. 15. Therefore, the size of the cooling device becomes large. On the other hand, when an upper side fan is disposed on the upper side of the upper portion 220 and a lower side fan is disposed on the lower side of the lower portion 210, the lateral width of the heat pipe 200 can be made small. However, in this case, velocity distribution of the heat pipe 200 in the longitudinal direction becomes uniform, thereby decreasing the cooling effect of the cooling device.
On the other hand, in a cooling device described in JP-B2-4-70800, each of heat pipes is bent at the center portions to increase cooling capacity. However, when the amount of heat generated by the electronic parts is increased, a large number of heat pipes are necessary and the manufacturing cost of the heat pipes is increased by the bending of the heat pipes.